Trans-anal inflow catheter and method for intermittently triggering a reflex-coordinated defecation

ABSTRACT

A device for transanally introducing an infusion into the rectum of a patient, the device comprising an inflatable balloon having a waisted shape, two terminal sections of larger radius and, a middle section of a reduced radius, and is placed transanally, the distally adjoining radially enlarged balloon section being placed intrarectally and the proximally adjoining radially enlarged balloon section extracorporeally, wherein both balloon ends taper to the dimension of a shaft supporting the balloon and are fixed on the surface of the shaft such that as the balloon is filled, the two enlarged balloon sections move toward each other in opposite axial directions, and wherein the two radially enlarged balloon sections are enlarged relative to the middle balloon section, such that when the balloon is placed transanally, during the filling process the two radially enlarged balloon sections draw down over the middle, balloon section and contact each other, and to a method for filling the catheter balloon.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates, on the one hand, to a device for transanallyintroducing an infusion into the rectum or colon of a patient, saiddevice comprising an inflatable balloon having a waisted shape,particularly a dumbbell or hourglass shape, imparted by preformingduring production, with two terminal balloon sections of larger radiusand approximately spherical or discoid shape, and, disposed betweenthem, a middle, tapered balloon section that has a reduced radius and isplaced transanally, such that the distally adjoining radially enlargedballoon section is placed intrarectally and the proximally adjoiningradially enlarged balloon section extracorporeally, and, on the otherhand, to a method for filling the catheter balloon of such a device fortransanally introducing an infusion into the rectum or colon of apatient by means of a filling device.

2. Description of the Prior Art

Catheters for transanally administering an infusion into the straightintestine (rectum) or large bowel (colon) of a patient have been knownin a wide variety of embodiments for many years.

Inflow catheters can be implemented as simple tube elements, but forimproved retention of the catheter in the rectum they are also providedwith an intrarectally placed balloon element. Such balloon elementsprovide, in addition to an anorectally anchoring function, a certainsealing effect that retains in the bowel the fluid that has beenintroduced by the irrigation. The sealing capacity of inflow cathetersfitted with an exclusively intrarectal balloon component is inadequatein many cases, however, and must be created by the user by continuouslymanually repositioning the surfaces of the sealing balloon on the floorof the rectum or manipulating the position of the catheter shaft atopthe balloon.

A major risk associated with the use of ordinary commercial cathetersthat are inserted transanally in the bowel continues to be perforationof the bowel wall due to improper handling or the presence of previouslyinjured or similarly weakened bowel wall structures. Such perforationsof the intestine have been preventable heretofore only by suitableeducation and sensitization of the user with respect to this particularset of problems.

Over the past ten years, a novel infusion technology that goes beyondthe use of conventional transanal infusions has become established; inthis new approach, the reflex-coordinated, active evacuation of therectum and large portions of the left colon adjoining the rectum istriggered by intermittent, relatively small-volume, intrarectallyintroduced infusions. By consistent voiding of these segments of theintestine, the patient can thus be brought to a state of so-called“pseudo-continence” regardless of existing incontinence problems. Theso-called transanal irrigation (TAI) method can be performed by thepatient himself.

The function of the rectally instilled infusion medium, apart from somedegree of mobilization of stool, is primarily to moderately expand thewall portions of the rectal ampulla (the terminal rectum), which thenresults in the triggering of the physiological stool evacuation reflex(reflex triggering). Whereas the rectally placed infusion medium usuallycauses such reflex triggering within a few minutes, it take can muchlonger, up to 30 minutes or more, for the administered irrigation volumeto be fully voided from the rectum or colon. The relatively long timerequired for TAI limits its acceptance by many patients, and often rulesthis method out despite the fact that it is, as a rule, efficient foruse by the individual.

Another problem is that many users are not able to manually bringirrigation catheters of conventional design into an adequately sealingposition and keep them there.

Furthermore, as the balloon component of a conventional catheter isexpanded inside the rectum, a reflex-triggering expansion of portions ofthe bowel wall can occur when the filling process has only just begun,thereby leading, inter alia, to a reflex-like opening of the anus andthus sometimes causing the anchoring balloon to slip out of the rectum.

Furthermore, commercially available devices for intermittent transanalirrigation, such as, for example, Peristeen Anal Irrigation, made byColoplast, Denmark, are of relatively elaborate design, and are oftenonly conditionally suitable for use outside the patient's familiardomestic surroundings.

To improve user acceptance of transanal irrigation, a catheter techniquewould be desirable which, once the catheter shaft is inserted in therectum, holds it in its transanal position without the need forcontinuous repositioning, and both keeps the body of the shaft fromsliding on into the bowel, with potentially traumatic consequences, andreliably prevents the catheter from accidentally slipping out of theanus prematurely.

Greater convenience in terms of the transanal placement of the catheteris offered in this regard by inflow catheters having a double balloonarrangement. Here, two separate balloon elements, which are usuallyfilled simultaneously via a single filling lumen, are mounted in spacedrelation on the catheter shaft. These come to lie on both sides of theanal canal, i.e. the internal and the external, thus mutually taking onthe structures of the anus. When the wall of the balloon is expandedunder pressure, the usually elastic implementation of the balloonmaterial brings about a spherical enlargement of the balloon bodies andthus a certain axially exerted squeezing of the anus disposed betweenthe balloon bodies. The dislocation-proof positioning of the cathetershaft obtained with such catheters can be assumed to be relativelyreliable. A problem resides in the sometimes high filling pressuresneeded for the elastic expansion of the envelope, which are felt bypatients as an uncomfortable or even painful foreign body sensation.Further, the elastic expansion of the intrarectal balloon to a tightlyfilled sphere can lead to direct triggering of the defecation reflex,which, in turn, in the presence of simultaneous rectal contraction anddeclining sphincter muscle tone, will in the most unfavorable case causethe catheter to slide out and the irrigation fluid to be voidedprematurely. DE 10 2004 033 425 B4 describes a sealing system for themanagement of rectal or anal incontinence having a particular embodimentfor the tamponade of bleeding hemorrhoids, presenting a waisted balloonelement having a terminal intrarectal or preanal section. The balloonenvelope of the device is placed on the balloon-supporting shaft body insuch a way that during the filling process, the intrarectal balloonsegment moves in the direction of the rectal floor and there exerts atamponade pressure on the bleeding venous blood vessels. The preanalballoon segment concurrently moves toward the external anal opening. Theresult is a tamponade effect oriented axially to the anus from bothsides. In addition to the axial tamponade of the bleeding, the middle,waisted section of the balloon expands outward radially to the wall ofthe anal canal. It is preferably shaped with a diameter that exceeds thediameter of the opened anal canal. In the described device for the acutemanagement of venous anorectal bleeding, in the in-use state the tip ofthe shaft body protrudes freely and unprotectedly into the intestinallumen and poses a potential risk of injury.

WO 2007/118621 A1 describes a similar dumbbell- or hourglass-shapedballoon sealing system. The object there is to provide a seal againstinvoluntary leakage of stool for intermittent periods of a few hours inchronically anorectally incontinent patients. This managing device alsoprominently features the rolling movement of the terminal balloonsegments from both sides axially toward the anus. Here again, in thetransanally placed state, the tip of the shaft body supporting theballoon protrudes freely and potentially traumatizingly into theintestinal lumen.

Both devices describe an hourglass- or dumbbell-shaped balloonconfiguration, the anus being received in the waisted region of theballoon, i.e. the region that is tapered relative to the terminalportions thereof. Such shaping of the balloon not only results inrelatively good securing of the catheter against dislocation, due to thesealing of the balloon inside the anal canal on all sides, but alsomakes for a considerable improvement in sealing performance over that ofconventional double balloons. In addition, both devices make it possibleto largely avoid any expansion of the balloon envelope that couldtrigger irritation, pain or a defecation reflex, since the balloon wallis preferably already shaped to its working dimensions or beyond. Thus,the filling or unfolding of the balloon to its working state requiresonly a low filling pressure, equal to or only slightly greater than thepressure prevailing in the rectum or abdomen at the time.

Nevertheless, a particular disadvantage of the embodiments described inDE 10 2004 033 425 B4 and WO 2007/118621 A1 has proven to be that thedistal tip of the shaft body supporting the balloon becomes freelyexposed during the filling process and protrudes into the intestinallumen, potentially causing irritation or injury to the bowel wall thereduring use.

SUMMARY OF THE INVENTION

The problem initiating the invention is to eliminate these disadvantagesof the known prior art.

This problem is solved, in an arrangement of the cited species, byvirtue of the fact that both balloon ends taper to the shaft dimensionof the catheter shaft supporting the balloon and are fixed in a simplyinvaginated or inverted manner on the preferably outer jacket surface ofthe catheter shaft in such fashion that as the balloon is filled, thetwo radially enlarged balloon sections move toward each other inopposite axial directions, and wherein the two radially enlarged balloonsections are enlarged relative to the tapered, middle balloon section,such that when the balloon is placed transanally, during the fillingprocess the two radially enlarged balloon sections draw down over themiddle, tapered balloon section and in the limit case come into directcontact with each other, thereby limiting their relative movement andpreventing the distal end of the catheter shaft from passing beyond theapex of the intrarectal balloon radius when the shaft body is in aposition of maximum axial deflection.

To prevent, insofar as possible, lesions due to the tip of the shaft,the invention describes a specific, particularly advantageous ratio ofthe length of the middle, waist-like balloon segment to the invagination(inversions), on both sides, of the fixation points of the ends of theballoon shaft to the catheter shaft. This ratio ensures that in thefilled, transanally positioned state, the tip of the catheter shaftspontaneously retracts into the intrarectal balloon segment and isnestled atraumatically there. The atraumatic securing of the cathetertip inside the intrarectal balloon segment is also ensured according tothe invention when the shaft axis undergoes the deflections inside theanal canal that typically occur during use, of the kind readily causedby a tug or push on the tube connection through which the catheter isguided in.

The invention further addresses the problem of preventing undesired orpremature triggering effects due to the filled balloon as it unfolds inthe rectum. Triggering of the defecation reflex can be prevented in mostcases by preshaping the balloon to the working dimension or beyond(residual dimensioning), since the filling pressures necessary foranchoring and sealing the catheter are largely the same as, or need beonly a few millibars higher than, the pressures prevailing in the rectumor in the abdomen. The atraumatic securing of the tip of the catheter inthe region of the intrarectal balloon segment is ensured even at suchlow filling pressures of, for example, 10 to 25 mbar.

Shaping the balloon to its working dimension further makes it possiblefor the user, by increasing the filling pressure or fill volume of theballoon from the initial filled state in which the balloon primarily hasa sealing and anchoring effect, to induce a well-controllable andgradually increasable expansion of the bowel wall adjacent the catheterballoon, ultimately leading to controlled triggering of the defecationreflex with individually adjusted intensity.

In addition to the initial expansion of the wall of the rectum, afurther suitable increase in the filling pressure in thedumbbell-shaped, waisted catheter balloon additionally causes a dilationof the anus or the anal sphincter, constituting another efficienttrigger stimulus.

The intensity of such pneumatic expansion of the bowel wall or the anuscan substantially exceed the intensity of reflex-triggering expansionwith fluid media. Due to the more intense stimulus, several sequentiallyoccurring cycles of evacuation reflexes can be triggered even though thestimulation is given only once.

This pneumatic expansion stimulus that can be well controlled by theuser can also reduce the necessary amount of infusion fluid in manycases, which in turn can considerably shorten the time needed toevacuate the infusion from the rectum, thereby ultimately opening up themethod to many users as a therapeutic option for self-administration.

The optional combined pneumatic/liquid triggering of reflexes describedhere eliminates the need for elaborate technical implementation ofirrigation appliances, since in the preferred use case the necessaryirrigation volume can be kept so small that it can be connecteddirectly, as a compact, ready-to-use solution, via a fixed feed conduitto an inflow catheter designed according to the invention, and thus, inan ideal manner, be used as a disposable product.

For this purpose, the irrigation solution is preferably filled into acylindrical, bag-like container, which the user can convenientlyintroduce intrarectally by squeezing it out with the hand.

The inflow catheter according to the invention further comprises apreferably fixedly glued-in filling conduit for charging the catheterballoon with filling pressure. The unit for filling the balloon ispreferably implemented in reusable form, and can be configured as ahand-operated pump balloon connectable via a coupling, or alternativelya pumped balloon with a pressure-indicating manometer. Alternatively,volume-controlled filling of the balloon is also conceivable. Regardlessof the filling arrangement, the user can determine by stepwiseapproximation the degree of filling of the balloon that is optimal forhim, that which is best adapted to his individual anatomy and hiscurrent reflex status.

To ensure the most practicable catheter insertion possible and thereliable transanal placement of the tapered portion of thedumbbell-shaped balloon element, the catheter shaft is preferablyequipped in the proximal, preanal region with gripping depressions toaccommodate the fingers gripping the catheter during insertion. If theuser has no sensitivity in the pelvic or anal region, he guides thecatheter in with his fingers until they abut the anus, and can thusavoid uncontrolledly deep insertion.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, characteristics, advantages and effects of theinvention will become apparent from the following description ofpreferred embodiments of the invention and by reference to the drawing.Wherein:

FIG. 1 a shows an embodiment of a catheter according to the invention ina schematic longitudinal section, the balloon ends being mounted on acatheter shaft in an inverted manner according to the invention;

FIG. 1 b shows the geometric structure of the apex of the distal balloonradius;

FIG. 1 c shows the balloon body described in FIG. 1 a in a freelyunfolded state under low filling pressure, outside the anus;

FIG. 1 d shows the balloon body described in FIG. 1 a in a transanallyplaced state, under filling pressure;

FIG. 1 e shows the geometric structure of the distal plane tangent tothe intrarectal balloon section;

FIG. 2 is a representation similar to FIG. 1 a of an alternativeembodiment of the invention, in which a catheter tip extends beyond theforward fixation line of the end of the balloon shaft;

FIG. 3 is a representation similar to FIG. 2 showing additionalauxiliary lines, such that the reference point for determining theinversion depth B is not the forward balloon radius, but rather thelargest diameter D of the intrarectal balloon segment;

FIG. 4 shows a shaped balloon envelope in the unfilled state, providedin a particularly advantageous manner for rectal insertion and reliabletransanal placement and unfolding of the balloon;

FIG. 5 shows an alternative embodiment of the invention with a cathetershaft waisted in its transanal section,

FIG. 6 shows a manually operable pump manometer with a pressure scaleequipped for multi-stage, sequential filling of the catheter balloon,and

FIG. 7 shows a further alternative embodiment of the invention with aninfusion container fixedly connected to the catheter shaft and a fillingtube for charging the catheter balloon with filling pressure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 a shows a longitudinal section through an inflow catheter with adumbbell- or hourglass-shaped balloon element 2 disposed at the distalend of the catheter shaft 1. The balloon element has, for example, aspherical or discoid expansion at each end. Disposed in the middleregion between the terminal enlargements is a cylindrically orapproximately cylindrically shaped segment 3 of reduced diameter, whichcontinuously connects the intrarectal enlargement 4 to the preanalenlargement 5.

The balloon 2 terminally comprises two balloon shaft ends (6, 7) forattaching the balloon to the shaft. During the mounting of the balloon,the shaft ends 6 and 7 are invaginated (inverted) into the inside of theballoon by a defined magnitude B and in this position, in which they aredisplaced toward each other, are fixed on the shaft 1, for example bygluing or welding.

The sum of the magnitudes B of the inversions at both ends should be atleast equal to the length of the tapered intermediate piece A (A smallerthan/equal to the sum of the magnitudes B).

The inversion depth B at the end of the balloon facing the patient orthe rectum corresponds to the distance from the apex 8 of the distal,intrarectal balloon radius 9 to the distal fixation line 11 of theballoon end 6 on the catheter shaft.

The distal radius 9 corresponds to the frontal radius during free,non-inverted unfolding of the completely filled but not pressurizedballoon (broken line). An exemplary rule for geometrically determiningthe apex 8 to good approximation is illustrated in FIG. lb. Inparticular, the drawing shows the two inflection points WP of thelongitudinal section through the distal balloon end, which, by theinversion of the distal region of the balloon, result in the sphericalor discoid or approximately semitoroidal region of the intrarectalsection of the balloon. The normals 9 e, 9 f to the tangent to thelongitudinal section of the balloon intersect with the longitudinal axisX of the catheter shaft at point M, and a circle K around this point Mat the distance M-WP yields the forward apex 8, which marks the distallimit for the catheter shaft in its neutral, non-deflected initialposition.

It can be seen in FIG. le that a straight line can also be passedthrough points WP; this straight line represents the plane Z which afterinvagination of the forward end of the balloon is now tangent distallyto the intrarectal portion of the balloon, and can also be taken as ameasure of the distalmost position of the catheter shaft in its neutral,non-deflected initial position.

On the side of the balloon facing away from the patient, the inversiondepth B corresponds to the distance from the apex 12 of the proximal,preanal balloon radius 13 to the proximal fixation line 14 of theballoon end 7 on the catheter shaft.

Radius 13 corresponds to the proximal radius when the balloon is freelyunfolded without inversion. The geometric determination of apex 12 issimilar to the approximation described in FIG. lb.

The length of intermediate piece A is determined by determining thedistance between the transitions of the shoulder radii 15 and 16(inflection points) of the mutually facing shoulder surfaces of balloonsegments 4 and 5.

The inversion depths, lengths and distances are each determined in thefilled state under filling pressure, the filling pressure being soselected that the balloon unfolds completely but there is no elasticexpansion of the balloon envelope.

The inversion depth B is calculated as follows: B>=A/2 (>=representsgreater/equal).

In mounting the balloon on the catheter shaft, the respective points forthe inversion of each of the balloon shaft ends are the apex 8 of thedistal, intrarectal balloon radius 9 and the apex 12 of the proximal,preanal balloon radius 13.

In the embodiment described in this figure, the distal fixation line 11also corresponds to the distal end of the catheter shaft 1. The shaftterminates directly at the fixation line 11 and does not extend distallypast this fixation line in the manner illustrated in FIG. 2.

FIG. 1 b describes the geometric derivation of the apex of the distalballoon radius.

The forward balloon radius 9, frontally facing the intestinal lumen, ofthe intrarectal balloon segment 4 is illustrated as a broken line. It isconstructed from the two inflection points 9 a and 9 b and the twoinflection tangents 9 c and 9 d respectively belonging to theseinflection points.

One of the two inflection points 9 a or 9 b is used to construct astraight line 9 e or 9 f that is normal to the respective inflectiontangent 9 c or 9 d and intersects the corresponding inflection point 9 aor 9 b. The point of intersection of these straight lines 9 e or 9 fwith the axis X of symmetry yields the center point of the circle K.

The circle K, and thus the forward balloon radius 9, results from thecenter point M of the circle and the inflection points 9 a and 9 b,which are on the circumference of the circle. In this derivation, apex 8is obtained from the point of intersection of the circumference of thecircle with the axis X of symmetry of the balloon.

For the description of the frontal apex 8 used below, the derivation ofthe farthest distally ranging point of the filled, unpressurized balloonenvelope is performed, for purposes of simplification, using the pointof intersection of the connecting line Z between the two inflectionpoints 9 a and 9 b with the axis X of symmetry.

FIG. 1 c shows the behavior of the catheter balloon that was invertedaccording to the invention in FIG. 1 a as it unfolds freely and withoutpressurization, in the free, non-transanally placed state. The figureillustrates the counter-rolling movement of the two terminal balloonsegments 4 and 5 made by possible by the specific inversion of theballoon ends 6 and 7 on the catheter shaft.

In a preferred, particularly thin-walled and soft-film-likeimplementation of the balloon body, the two segments move toward eachother in response to the slightest, nearly ambient filling pressure androll over the middle segment 3. When the two segments are in contact inthe region of the transition points (15, 16) of the shoulder radii, theapex 8 of the radius 9 is flush or nearly flush with the distal fixationline 11 of the distal balloon shaft end 6 on the catheter shaft.

A configuration of this kind would correspond in situ to a clinical usesituation in which the anal canal was maximally shortened in length.Even in this extreme case, it would thus be ensured by virtue of thedescribed inversion rule that the free distal catheter shaft end, whichhere corresponds to the distal fixation line 11, does not extend intothe intestinal lumen and even in the event of maximal lateral deflectionof the catheter shaft in the rectum (tilting of the intrarectal portionof the shaft toward the bowel wall) does not come into contact with thewall of the intestine and pass beyond the distal balloon radius 9, as amaximum limit precluding irritation and lesions of the bowel wall.

FIG. 1 d shows how the inversion of the balloon ends in relation to thedistal catheter shaft ends described in FIG. 1 a presents itself incases where the anal canal is of normal or only slightly shortenedlength. In this more common clinical use situation, the forward fixationline 11, which here corresponds in turn to the distal free end of thecatheter shaft, is shown to be deflected substantially into the interiorof the intrarectal balloon 4. As the balloon is charged with pressure,the two terminal balloon segments 4 and 5 move counter to each othertoward the anus and so conform to the particular anal situs. Given asuitably thin-walled implementation and soft-film-like character of theballoon envelope, the counter-rolling of the balloon segments commenceseven in response to a very low pressure force (filling pressure) thatgives an impression of being nearly ambient to the environment.

The mere individual intra-abdominal pressure bearing against thetransanally placed balloon or acting on the balloon is sufficient toproduce a combined transanal sealing effect, comprised of radial sealingwith respect to the anal canal and axially oriented sealing broughtabout by the counter-rolling movement of the terminal balloonenlargements at the inner and outer outlets of the anus. The sealingeffect thus is not contingent on the balloon initially being filledbeyond its volume and unfolding freely until the balloon envelope beginsto expand. The balloon can behave in the described axial counter-rollingand radial unfolding fashion, even under partial filling of, forexample, 70 to 90% of its volume when freely unfolded on the cathetershaft. This enables the balloon catheter to be placed in the anus in anearly pressure-neutral and irritation-free manner.

In the presence of normal or slightly modified anal anatomy, anytraumatizing effect of the tip of the catheter shaft on the bowel wallcan thus be precluded, even under completely pressure-neutral chargingwith a filling medium, by the inversion of the shaft tip that occursaccording to the invention.

FIG. 2 shows, by way of example, how sections of the catheter shaft inthe form of a tip piece 18 that extend beyond the distal fixation line11 in a distal prolongation directed toward the bowel are to beconsidered in determining the inversion depth of the balloon ends 6 and7, in order to ensure atraumatic inversion, according to the invention,of the distal end of the catheter in the intrarectal balloon duringtransanal placement of the filled catheter balloon. The length C of thetip piece 18 is defined as the distance from the forward fixation line11 to the forward apex 19 of the tip piece.

Length B is increased in comparison to FIG. 1 a by the magnitude oflength C or C/2.

The corresponding inversion depth B is preferably calculated taking intoaccount a tip piece in the form: B>=A/2+C.

Alternatively hereto, the corresponding inversion depth B can, lesspreferably, be obtained considering a tip piece according to therelation: B>=A/2+C/2.

FIG. 3 illustrates another, alternative rule for establishing theinversion depth B of the balloon shaft ends 6 and 7 on the cathetershaft 1 in relation to the distal catheter shaft end 11, 19.

This rule particularly considers a possible axially oriented deflectionof the catheter shaft inside the filled, transanally placed balloon. Inthe context of the inventively described inversion of the balloon shaftends on the catheter shaft supporting the balloon, such deflection ofthe shaft in the longitudinal axis could cause the distal end of thecatheter shaft to be deflected toward the bowel, thus creating apotential risk of perforation.

The maximum distal deflection W of the forward fixation line 11 isdefined as a distance that emanates from the apex 8 of the radius 9,forming a distally directed prolongation of the longitudinal axis of theshaft, and extends to the apex 20 of a radius 21, said radius 21 beingconstructed over the largest diameter D of the intrarectal balloonsegment 4.

If the catheter shaft has a tip piece 18 that extends beyond line 11,the maximum deflection path W should be correspondingly selected so thatupon maximum deflection W of the shaft, the tip 19 of the tip piece doesnot extend past radius 21.

The radius 21 defined by the largest diameter D in the intrarectalballoon segment constitutes a fundamentally relevant boundary line fordistal portions of the catheter shaft. In the event of lateral tiltingof the shaft longitudinal axis of the transanally placed catheter shaft,the fact that the maximum deflection W is referred to the largestballoon diameter D ensures that the catheter shaft tip (11, 19) stillmoves within the pivot radius 21 of balloon segment 4, thus preventingrelatively well any potential traumatizing contact of the tip with thebowel wall adjacent the balloon.

In determining the inversion depth B, the particular ratio of thedistance W to the radius 21 or of the diameter D on which it is based ispreserved and the inversion depth B is adjusted accordingly asnecessary.

FIG. 4 shows the catheter balloon 2 in its emptied form, in which itlies against the catheter shaft ready for insertion in the anus. Theenvelope segments of the intrarectal balloon 4 and of the middle segment3 cling to the shaft in folds.

In this state, the two envelope portions preferably come to lieapproximately at the height of the line segment between the fixationpoints of the balloon ends 6 and 7 on the surface of the shaft. Theenvelope of the preanal balloon segment 5, by contrast, is preferablysmoothed out in the proximal direction and protrudes past the fingersgripping the catheter for insertion, the preferred gripping point beinglocated just proximal of the proximal fixation line 14. The grippingpoint 22 is preferably implemented as a depression-like receivingsurface, one such preferably being provided on each of the opposite,180°-apart shaft surfaces.

The evacuated balloon being fixed in such fashion, the user grips withhis fingers under the envelope of segment 5, which envelope is smoothedout in a proximal direction, and guides the catheter into the rectumuntil the gripping fingers abut the external anus. A defined insertiondepth is thereby ensured. It is further ensured that the intrarectalballoon section 4 is inserted into the rectal cavity, while the proximalballoon portion 5 comes to lie outside the anus (preanally). Reliabletransanal positioning of the catheter therefore occurs as the waistedballoon is filled.

FIG. 5 shows a preferred implementation of the shaft body 1 thatfurnishes some degree of automatic positioning and securing of the shaftin the anus even when the catheter balloon has not yet been filled. Theshaft 1 has for this purpose a likewise waisted shape, which iscorrespondingly tapered in the transanal region 23 and in effect locksthe catheter shaft in a transanal position in this region afterinsertion. The catheter shaft preferably also has a distally terminal,funnel-like, atraumatically shaped opening 24 that connects to the duct25 supplying the medium.

In a particularly large-volume implementation of the intrarectal balloonsegment or a longitudinal expansion of the balloon segment that reachesfar into the rectum, the balloon segment, in the non-air-filled,ready-to-use state, can optionally be stuffed or packed partially intothe opening 24. It then slips out of the opening as the insertedcatheter is filled.

Given suitable implementation of the shaft material, the waist 23 canalso predefine a certain kinkability of the shaft body, thus improvingits atraumatic properties.

The filling of the balloon takes place through a separate duct 26integral to the shaft.

To prevent backflow of irrigation fluid, the inflow catheter can is[sic] equipped with a non-return valve in the region of thefluid-conveying duct 25.

The valve can preferably consist of a thin-walled tube element having awall thickness of few, preferably, 5 to 15 micrometers and the diameterof the duct 25, the distal end of the tube lying freely in the duct 25over a length of approximately 5 to 10 mm and its proximal end beingconnected sealingly to the inner wall of the duct 25. As the mediumflows through the duct in the direction of the tip, the tube elementopens and allows the medium to flow freely. In response to flow in thereverse direction, the tube element collapses and closes up sealingly,preventing an effective backflow.

FIG. 6 schematically illustrates a pump manometer 27 equipped with ascale 28 suitable for the filling of the inventive catheter balloon inmultiple steps or with a sequential increase in filling pressure. Thescale preferably displays, on the one hand, an initial, low pressurerange 29 (app. 10-25 mbar), which is set by the user after inserting thecatheter and before introducing the infusion fluid, and which, given theinventive preshaping of the balloon envelope and its fixation on theshaft, is sufficient in most cases to ensure transanal anchoring andsealing of the catheter without a direct reflex-triggering effect on thebowel wall.

When the user then initiates an increase in the filling pressure in theballoon into range 30 (30-60 mbar, with increasing correspondingexpansion of the rectal portions of the bowel wall) or into range 37(60-120 mbar, with increasing additional expansion of the analsphincter), the user is ultimately able to generate a trigger stimulusof largely reproducible intensity in order to trigger a defecationreflex. The user thus has the advantage of being able to avoid anevacuation reflex in the presence of an initially low balloon pressuremerely having an anchoring and sealing action, and thus of being able toretain the infusion fluid in the bowel long enough for his individualneeds, resulting in better dissolution or suspension of stool in thefluid. On the other hand, by intentionally causing an increase inpressure in the balloon, he can generate an intense, relativelyprompt-acting reflex-triggering stimulus, which can, if necessary,exceed in intensity the triggering effect of a column of colorectalfluid.

The catheter balloon is preferably filled with air, through a fill lineintegrated into the shaft wall of the catheter body 1.

In addition to pressure-controlled filling of the balloon using a pumpmanometer, as illustrated in FIG. 6, volume-controlled filling can beachieved with the use of an additional syringe element that specifiesthe preferred fill volume by means of a suitable marking on the syringebody. The filling of the balloon is preferably partial, in the form ofone-step filling. In the ideal case, therefore, in loose, unexpandedform, the balloon lies against the structures of the bowel and the anus.The balloon envelope thus absorbs the forces acting on the balloon inthe rectum, the anus and the preanal region and brings the balloon intothe configuration in which it performs the anchoring and sealingfunction. The respective physiologically acting forces are absorbed bythe catheter balloon and thus enable the balloon to be placedanorectally in as pressure-neutral a manner as possible, largelyprecluding undesired and premature triggering effects.

A volume-controlled filling of the balloon can also be a two-stepprocess, in which incomplete filling is first performed and the balloonis then, in the second filling step, filled with a volume that has atriggering effect. The pressures developed in the transanal balloon inresponse to the particular volume should preferably fall within thepressure ranges (29, 30) described in FIG. 6, and are to be determinedby and for the user on an individual basis, as in the case ofpressure-controlled filling.

To limit the filling pressure or prevent critically high balloon fillingpressures, in the case of both manometer- and syringe-actuated filling apressure limiting valve 31 can be interposed between the filling elementand the catheter, to prevent, for example, balloon filling pressuresover 120 mbar.

FIG. 7 shows a preferred embodiment of an inflow catheter, whichtransitions at the proximal end to two feed conduits that are preferablyfixedly connected to the shaft, feed conduit 32 being fixedly connectedto a preferably bag-like container 33 containing infusion medium, andthus constituting a ready-to-use unit comprised of catheter and medium.

The volume of the container 33 must be dimensioned in this case toaccommodate approximately 80 to 120 ml of irrigation solution. Therelatively small quantity is squeezed out manually by the user and thusintroduced into the rectum by repeated squeezing. To make it possible togrip the container even with impaired hand motor function, the containeris preferably shaped as cylindrical, with a diameter of approximately4-6 cm.

Connection 32 is preferably equipped with a seal 35 that can be brokenby bending and that releases the irrigation solution. It is alsoadvantageous to provide a non-return valve 36, which is integrated intothe fluid-conveying arm of the ready-to-use device and which permits thedirected emptying of the container without backflow.

Another feed conduit 34 can be connected directly to a pump manometer 27or a filling syringe.

The balloon element 2 consists of a thin-walled soft film in the wallthickness range of 5 to 100 micrometers. Films in the thickness range of5 to 40 micrometers are advantageous. Wall thicknesses of 5 to 15micrometers, on the other hand, are particularly preferable.

The use of only slightly volume-expandable materials, such as, forexample, polyurethane (PUR), for example of the specification Pellethane2363 80 A to 90 A, Dow Chemical Corp., is preferred, since thesematerials have good dimensional stability in the lowest wall thicknessrange, including as balloon films, in the pressure range ofapproximately 10 to 120 mbar.

Such thin-walled PUR balloon films formed into complex shape canpreferably be produced by hot molding from previously extruded rawtubing material, which, with suitable stretching of the tube blankbefore tempering, permits a polymer orientation and lends the shapedballoon films exceptional mechanical strength.

It is also conceivable to use polyurethanes of low Shore hardness, forexample in the range of 60 to 75 A, to impart a volume-expandablebehavior, with a relative loss of dimensional stability, to the catheterballoon in the wall thickness range of less than 40 μm, and preferablyless than 15 μm, in the typical filling pressure range during use of 10to 120 μm.

Alternatively, for example non-volume-expandable materials can also beused, such as polyethylene, PVC or mixtures of the aforesaid materialswith polyurethane.

Balloon films according to the invention can also be shaped directlyfrom the extruded, still soft, largely amorphous tube molding compound(in-line molding), in which case the achievable strengths of the filmsare much lower than those of pre-extruded tubes and the attainable wallthicknesses are much higher than in the case of forming frompre-extruded material.

Dipping processes using liquid PVC or PUR materials can also becontemplated for production.

The welding together of single layers of film to form balloon bodies isalso conceivable.

The connection of the balloon to the shaft body is effected by gluing,by thermal methods, or alternatively by shrinking the balloon ends ontothe shaft body.

In the freely unfolded, unpressurized state, the balloon shouldpreferably have a diameter of approximately 30-60 mm in the intrarectalsection 4, approximately 10 to 30 mm in the middle, waisted region 3,and approximately 30-50 mm in the preanal region 5. The middle segment 3should have a length of approximately 20-40 mm and each of the terminalsegments 4 and 5 a length of approximately 20-40 mm.

If, as a special measure for sequential filling, the catheter balloon isprovided with optional intrarectal balloon triggering, the intrarectalballoon section 4 in the freely unfolded, unpressurized state preferablyhas a diameter of approximately 40-80 mm and a length of preferably30-60 mm.

In addition to the transanal use of the inflow catheter, the embodimentsaccording to the invention can also be used for perforation-safeplacement of a transanally inserted drainage tube for, among otherpurposes, the ongoing drainage of stool from a patient's intestine.Further, the described catheter technique may also be contemplated foruse in surgically created stomata/openings or other natural bodyopenings.

1. A device for transanally introducing an infusion into the rectum orcolon of a patient, said device comprising an inflatable balloon havinga waisted shape, comprising two terminal balloon sections of largerradius and generally spherical or discoid shape, and, disposed betweenthem, a middle, tapered balloon section having a reduced radius, thedevice being adapted to be placed transanally, such that the distallyadjoining radially enlarged balloon section is placed intrarectally andthe proximally adjoining radially enlarged balloon sectionextracorporeally, wherein both balloon ends taper a shaft dimension of acatheter shaft supporting the balloon and, beginning at an inflectionpoint of their longitudinal section, are inwardly invaginated, orinverted, and in the inverted or invaginated state are fixed on theouter jacket surface of the catheter shaft such that as the balloon isfilled, the two radially enlarged balloon sections move toward eachother in opposite axial directions, and wherein the two radiallyenlarged balloon sections are enlarged relative to the tapered, middleballoon section, such that when the balloon is placed transanally,during the filling process the two radially enlarged balloon sectionsdraw down over the middle tapered balloon section and come into directcontact with each other, thereby limiting their relative movements, as aresult of which the distal tip of the catheter shaft, in itsnon-deflected, resting state, retracts into a protected,injury-preventing position inside the intrarectal balloon section and inso doing comes to lie entirely proximally of a distal apex of a circleabout a center point which is located on an axis of symmetry and whosetangent in an inflection point corresponds to a tangent to thenon-invaginated longitudinal section of the balloon.
 2. The deviceaccording to claim 1, wherein a distal tip of the catheter shaft in itsnon-deflected, resting state comes to lie entirely proximally of a planewhich is intersected perpendicularly by the axis of symmetry and whichis fully tangent distally to the intrarectal balloon section.
 3. Thedevice according to claim 1, wherein the middle, tapered balloon sectionis separated from each of the generally spherical or discoid balloonsections by a respective inflection point of the cross-sectional radius,and in the non-expanded filled state exhibits an axial length largerthan a minimum diameter thereof.
 4. The device according to claim 1,wherein the non-expanded filled state, the invaginated or invertedballoon ends each have an axial extent (B₁, B₂) greater than a minimumdiameter thereof.
 5. The device according to claim 1 wherein in thenon-expanded filled state, the sum of axial extents (B₁, B₂) of theinversions of the two balloon ends is at least equal to the length ofthe middle, tapered balloon section (A):B ₁ +B ₂ ≧A.
 6. The device according to claim 2, wherein the catheterdistal tip projects by a dimension (C) beyond a forward fixation line ofthe forward balloon end on the catheter shaft, and the inversion depth(B) is greater than, or equal to, half of balloon section length (A)plus the length (C) of a projecting tip piece (18):B ₁ =B ₂ ≧A/2+C, or alternatively:B ₁ =B ₂ ≧A/2+C/2.
 7. The device as according to claim 1, wherein uponaxial deflection of the catheter shaft toward the bowel in response toforces that occur during use, a catheter tip does not move more than adistance (W) beyond the distal apex of the forward balloon radius, andthe distance (W) is obtained from the distance between the distal apexand an apex comprising a forward intersection point of the axis ofsymmetry with a circle of diameter around a center point on the axis ofsymmetry at the level of the attachment of the intrarectal balloonsection to the catheter shaft.
 8. The device according to claim 1,wherein the envelope of the evacuated, ready-to-use catheter balloon isplaced on the shaft, or clings closely thereto, in such fashion that theintrarectal and the transanal balloon sections lie in a shaft regionbetween the fixations of the upper and lower balloon ends, and a preanalballoon portion extends in the proximal direction in a pocket-likemanner over gripping depressions.
 9. The device according to claim 8,wherein the gripping depressions are disposed on the shaft in directproximal adjacency to a rear balloon fixation line.
 10. The deviceaccording to claim 1, wherein the catheter shaft is provided with awaist portion in the region of the transanal placement inside the analcanal.
 11. The device according to claim 1, wherein inserted in a ductof the catheter shaft is a non-return element adapted to preventretrograde backflow of fluid directed away from the patient through thecatheter.
 12. The device according to claim 11 wherein the non-returnelement in the duct comprises a thin-walled tube element having a wallthickness of 5 to 15 micrometers, and having a diameter of the duct,such that the distal end of the tube lies freely in the duct over alength of approximately 5 to 10 mm, and the tube proximal end issealingly connected to an inner wall of the duct, thereby ensuring thatthe tube element opens in the presence of a flow of medium through theduct toward a tip thereof, and the tube element closes by collapsing inthe presence of flow in an opposite direction.
 13. The device accordingto claim 1, wherein the catheter is connected by a fixed tube connectionto a bag-like container for irrigation fluid, as a ready-to-use,disposal product.
 14. The device according to claim 13, wherein thefixed tube connection is provided with a breakable seal and/or with anon-return valve.
 15. The device according to claim 1 wherein thecatheter comprises a disposable catheter, connectable via a fillingconduit to a reusable filling device, the filling device beingimplemented as a manually operable pump balloon with a manometerindicating balloon filling pressure.
 16. The device according to claim15, and comprising a manometer indicating the balloon filling pressure,wherein the manometer comprises a scale on which the filling pressureranges required for use of the catheter are specified by markings. 17.The device according to claim 1, wherein a valve element limits theballoon pressure, and is disposed in or on a reusable filling device oris integrated into a selected one of the balloon filling conduit of thesingle-use catheter and the catheter-bag unit.
 18. A method for fillingthe catheter balloon of a device for transanally introducing an infusioninto the rectum or colon of a patient by means of a filling device,wherein a fill volume or the filling pressure prevailing in the balloonis increased in a plurality of steps until there occurs a gradual,user-controllable, pneumatically initiated expansion of portions of thebowel wall, thereby triggering a coordinated defecation reflex, whereinthe timing and intensity of the triggering can be determined by theuser.
 19. The method according to claim 18, wherein: a) the pressure inthe transanally placed catheter balloon is initially set to a first, lowpressure range of approximately 10 to 25 mbar, which anchors and sealsthe catheter in the anus; b) the inflow fluid is introduced into therectum by squeezing it out of the container; c) after a suitableretention time, the filling pressure in the catheter balloon is raisedto approximately 30 to 60 mbar, causing only the rectal bowel wall to beinitially included in the expansion, and at which the defecation reflexis triggered in most users; d) upon a further increase in the fillingpressure in the catheter balloon, to approximately 60 to 120 mbar, theanal canal is also caused to expand, to increase intensity of thestimulus triggering the defecation reflex.
 20. The method according toclaim 19, wherein by the sequential pneumatic triggering of a defecationreflex, a volume of the irrigation fluid is reduced to a value of about80 to 120 ml per administration, the fluid being delivered asready-to-use solution through a fixed feed conduit to the catheter, andthe balloon is disposable.